Attack on ships at port....what am I doing wrong?

[chowderhead62]

So I received a mission to drop an agent in Panang....I snuck in at night and dropped the agent, evaded two subchasers, and on my way out there were a number of large ships docked in Panang. I snuck in under cover of weather and fog and put one of the large ships dead in front of me. It wouldn't let me target lock the ship until visible, so I tried two things. 1) Firing torpedos straight ahead and it looks from the target map they went straight ahead, but none of them hit the target....I didn't get dud messages they just exploded beyond the target. so then I tried waiting until I could actually get a target lock, which I did and then fired, to no avail. Any ideas? Could it be mines in the harbor? a sea wall? I can't seem to figure it out!

Sincerely,
One suck ass Captain.